Sylvania



(No Model.)

FLEXIBLE SUPPORTING ARM POR ELECTRIC LAMPS. No. 172,611l Patented Apr..12, 1892.

ffy 1 UNITED 'STATES PATENT OFFICE.

LCIUS T. STANLEY, OF BROOKLYN, SEXY YORK, ASSIGNOR TO T IIE CUTTIll-ELECTRIC AND MANFACTURIN G COMPANY, OF PHILADELPHIA, PEi\\f SYLVANI.

FLEXIBLE SUPPORTING-ARM FOR ELECTRIC-LAMPS.

SPECIFICATION forming part of Letters Patent No. 472,611, dated April12, 1892.

I Application filed October 17, 1891. Serial No. 409,034. (No model.)

To all whom it may concern.-

Be it known that I, LUCIUs- T. STANLEY, a citizen of the United States,and a resident of Brooklyn, in the county of Kingsand State of New York,have invented certain new and useful Improvements in FlexibleSupporting- Arms for Electric Lamps and other Devices, of which thefollowing is a specification, reference being had to the drawingsaccompanyio ingand forming a part of the same.

This invention is an improvement in flexible hollow arms more especiallydesigned vas supports for incandescent lamps, whether when used as awall-bracket or when forming i5 part ot' any fixture or device, such asa desk or table lamp-stand; but while the nature of the improvementswhich l have made in 'these devices renders them equally serviceable anduseful as the flexible supports for portable lamp and tool stands,lens-holders, and analogous devices, to all of which purposes Icontemplate applying the invention, it is more particularly useful as apart of an electrical fixture from the fact that it is hollow throughoutfor the passage of one or more conductors and that such passage is notclosed or obstructed by bending the arm in any way that may be desired.

My improved flexible arm consists of a hollow core composed of a givennumber of strands of wire, preferably copper, wound spirallyand in themanner hereinafterdescribed to forin a tube or cable, which is containedWithin a'u outer spiral of steel or similar resilient wire and securedat.both ends .to the ends ofv said outer spiral. The said core alsocontains a spiral spring of steel or similar wire,

the ends of which are secured to those of the core, and both the innerand outer spirals are normally shorter than the intermediate tubularcore, so that they require to be forcibly elongated in order to securetheir ends to those of the core.

For a more specific description ,of the construction and mode of usingthe invention I now refer to the accompanying drawings.

Figure 1 is a longitudinal central section of a portion of a flexiblearm constructed in accordance with my invention. Fig. 2 is an end 5oview of the same, and Fig. 3 is a view in elevation of the arm used as asupport for an electric lamp.

A is a hollow tube or core made up of sevcral strands of coppeiorothersuitable ductile or pliable wire wound spirally on a mandrel and at apitch determined by the particular service for which the arm isdesigned. For example, if the completed arm is designed for a use inwhich it will be bent only slightly, as at right angles to itself, thepitch would be 6oinuch shorter and the wires would have a much greaternumber of turns to the inch than in the case of an arm which is designedto b e bent up into a coil, say, of two inches in diameter.

In practice I have found that for the ordinary purposes of a iexible armfora wallbracket orlamp-stand the proper pitch for the strands of thehollow core or cable is about one turn in two and a half inches. Thisallows the completed arm to be bent into a coil of about two and a halfinches diameter without subjecting the copper strands to any injurioustensile strain. l

Within the hollow core A is a spiral spring B of steel or other elasticwire. This spiral is relatively shorter than the core or cable A, and itmust be distended tobring its twoends even with those of the core A.

C is an outer covering of steel or other elastic wire iu the form, also,ofa spiral. Similarly to the spiral B it is made shorter thanl the coreA and has to be distended to equal it in length. The ends b b of thespiral B are bent outward and the ends c c of spiral C are bent inwardover the ends of the core A, so as to hold them in position until theyare soldered or brazed into suitable sockets. The strands composing thecore .A are wound on a mandrel and the ends are soldered or brazedtogether to form a tube of the desired length.

In practice l have found the best relative lengths of core and spiralsto be as follows: It the core be sixteen inches, then each of thc twospirals should be about fourteen inches. With these proportions and whenthe strands of wire composing the core A have one turn for about two anda halfinclies the arm may be subjected to any reasonable amount ofbending without disturbing in any way the relative conditions of itsparte and without meeting any tendency to alter the shape or curve intowhich it has been bent.

In Fig. 3 one of the applications of the invention is illustrated. Oneend of the flexible arm is soldered into a stationary socket S, formingpart ofn wall-plate. The other end carries sind is soldered into nlamp-socket T, into which n lamp L may be iitted.

I do not limit myself to the special form and proportions herein stated;but by follow ing the general plany of construction herein described Iam enabled to produce e. flexible arm that is durable, strong, andserviceable, and which maybe substituted for any of the jointed armsheretofore in use.

"hat I claim is- 1. A iexible snpportingarln consisting of :L hollowcore formed of spirally-wonnd strands of ductile wire, in combinationwith an outer spiral of resilient wire, as set forth.

2. A iiexible supporting-arm eonsistingof n hollowcore formed ofspirally-wound strands of duetile wire, in combination with an outerspiral of resilient wire distended and havingIr its ends secured tothose of the core, as set forth.

3. A flexible supporting-arm consisting of a hollow core formed ofspirally-wonnd strands of ductile wire, in combination with an outerspiral of resilient wire having ashorter pitch than the wires of thecore, as set forth.

4. The combination,with a'dnetile core composed of spirally-woundstrands andan outer spiral of resilient wire, of an inner support* ing,rresilient spiral, both inner and outer spirnls being distended andsecured to the ends of the core, as set forth.

LUCIUS T. STANLEY. litncsses:

FRANCIS G. GALLAGER, GEO. H. WENTZ.

